Thermoplastic resin composition for reduction of squeaking noises and structure of reduced squeaking noises

ABSTRACT

Provided is a thermoplastic resin composition [X] for reduction of squeaking noises containing a rubber-reinforced vinyl resin [A] obtained by polymerizing a vinyl monomer [b1] in the presence of an ethylene-α-olefin rubber polymer [a1] having Tm (melting point) of 0° C. or higher, wherein an amount of silicon contained in the thermoplastic resin composition [X] is 0.15% by mass or less based on 100% by mass of the thermoplastic resin composition [X]. According to the present invention, a structure can be provided, which is characterized in that squeaking noises that are generated when members rub against each other is remarkably reduced, that an effect of reducing squeaking noises is maintained without deterioration even when placed under high temperature for a long time, and that impact resistance and molded appearance are superior.

TECHNICAL FIELD

The present invention relates to a thermoplastic resin composition forreduction of squeaking noises and a structure of reduced squeakingnoises made of the thermoplastic resin, and more particularly, to athermoplastic resin composition for reduction of squeaking noises whichis remarkably capable of reducing squeaking noises caused by coming intocontact with and rubbing at least two parts, and a structure of reducedsqueaking noise made of the thermoplastic resin.

BACKGROUND ART

Styrene resins represented by ABS resin are widely used for theproduction of automobiles, household electrical appliances, OAequipments or the like due to its superior moldability, mechanicalproperties, chemical resistance and secondary processability.

However, when parts of styrene resins represented by ABS resin come intocontact with and rub against another part made of other resins such aspolyethylene and polyvinyl chloride or another part such as a liningsheet or a foam made of chloroprene rubber, natural rubber, polyester orpolyethylene, squeaking noises (rubbing noises) may be generated. Forexample, in a ventilator made of ABS resin is installed a valve shutterusing a chloroprene rubber foam or the like as a sealing material inorder to adjust an air quantity. If the valve shutter is rotated for airquantity adjustment, a case of the ventilator rubs against the sealingmaterial, so that squeaking noises may be generated.

Moreover, it is known that when parts made of styrene resins rub againsteach other, squeaking noises tend to be generated. Therefore, it isavoided to use parts made of styrene resins in combination in placeswhere the parts come into contact with and rub against each other, forexample, by vibration, rotation or the like.

Since the styrene resins such as ABS resin and ASA resin are amorphousresins, they are higher in coefficient of friction as compared withcrystalline resins such as polyethylene, polypropylene and polyacetal,and it is well known that, like an air outlet of an air conditioner inan automobile or buttons of a car audio system, when fitting with amember made of another resin, a stick slip phenomenon as illustrated inFIG. 1 occurs to generate unpleasant sounds (squeaking noises) becauseof a large coefficient of friction. The stick slip phenomenon is aphenomenon that is generated when two objects rub against each other. Asillustrated by a model of FIG. 2(a), when an object M connected with aspring is placed on a driving table that moves at a driving speed V, theobject M moves toward the right direction first as illustrated in FIG.2(b) together with the table moving at the driving speed V by the actionof a static frictional force. When the force by which the object M is tobe restored to its original position becomes equal to the staticfrictional force, the object M starts to slip in the opposite directionto the driving speed V. At this time, the object M comes to receive akinematic frictional force, and the slip is stopped when the force ofthe spring becomes equal to the kinematic frictional force asillustrated in FIG. 2(c), so that the object M comes again into a statewhere it attaches on the driving table and it moves again in the samedirection as the driving speed V (FIG. 2(d)). This is called a stickslip phenomenon. As illustrated in FIG. 1, it has been said that if thedifference Δμ between the coefficient of static friction μs of the upperend of a saw wavy form and the coefficient of friction μ1 of the lowerend of a saw wavy form is large, squeaking noises tend to be generatedeasily. A dynamic friction coefficient is a middle value between μs andμl.

When those are used as automobile interior parts and the like, such asqueaking noise is a major cause that spoils comfortableness and silencewhen riding a car, and therefore reduction of squeaking noises isdemanded strongly.

On the other hand, it is known that the stick slip phenomenon occursremarkably when the friction velocity dependency of a coefficient offriction determined on the basis of the Amonton-Coulomb's law takes anegative value (see non-patent document 1), and it is possible toinhibit the occurrence of the stick slip phenomenon and reduce thegeneration of squeaking noises by bringing the friction velocitydependency of the coefficient of friction close to zero or to a positivevalue greater than zero.

In order to prevent such squeaking noises, a method of applying Teflon(registered trademark) coating to the surface of a member, a method ofmounting a Teflon (registered trademark) tape, a method of applying asilicone oil, etc. have been performed. However, the step of mounting orapplying is very complicated and requires time and effort, and there isa problem that the effect does not continue when being placed under hightemperatures for a long time.

As a method for changing the properties of the material itself, a methodof incorporating a silicone oil into an ABS resin and a method ofincorporating an epoxy-containing olefin copolymer into an ABS resinhave been proposed. For example, there have been disclosed a technologyof incorporating an organosilicon compound into a resin composed of apolycarbonate resin and an ABS resin (see patent document 1), atechnology of incorporating a flame retardant, a flame retarding aid anda silicone oil into an ABS resin (see patent document 2), a technologyof incorporating a silicone oil into a rubber-modified polystyrene resin(see patent document 3), a technology of incorporating an alkali (earth)metal salt of an alkane sulfonate surfactant into an ABS resin (seepatent document 4), and a technology of incorporating a modifiedpolyorganosiloxane having at least one reactive group selected fromamong an epoxy group, a carboxyl group and an acid anhydride group intoan ABS resin (see patent document 5).

However, an effect of reducing squeaking noises obtained by thesemethods is not sufficient. Even if the effect of preventing squeakingnoises is considerably exhibited just after molding, the durability ofthe effect is poor, and in particular, there is a problem that theeffect deteriorates remarkably when being placed under high temperaturesfor a long time.

Moreover, when the parts made of styrene resins represented by ABSresins are assembled in combination, even with those technologies, thesufficient effect of reducing squeaking noises cannot be obtained andthus there was a problem that the range of usage was limited.

PRIOR ART DOCUMENTS Patent Documents

-   Patent document 1: Japanese Examined Publication 63 (1988)-56267-   Patent document 2: Japanese Patent No. 2798396-   Patent document 3: Japanese Patent No. 2688619-   Patent document 4: Japanese Patent No. 2659467-   Patent document 5: Japanese Laid-open Publication 10 (1998)-316833

Non-Patent Documents

Non-patent document 1: Journal of The Surface Science of Japan, Vol. 24,No. 6, PP. 328-333, 2003

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In view of such situations, an object of the present invention is toprovide a thermoplastic resin composition which is capable of providinga structure of reduced squeaking noises, even when the parts of styreneresins are used in places where those rub against each other,characterized in that generation of squeaking noises that are generatedwhen members rub against each other is remarkably reduced, that aneffect of reducing squeaking noises is maintained without deteriorationeven when being placed under high temperatures for a long time, and thatexcellent impact resistance and molded appearance are imparted.

Solutions to the Problems

Meanwhile, silicone oil is blended in a resin composition for thepurpose of modifying, for example, increase in slidability of a moldedarticle. Moreover, it may be added to prevent deterioration anddiscoloration of a rubber-reinforced vinyl resin caused by raisedtemperature of the resin due to shear force in an extruder when therubber-reinforced vinyl resin is melted and kneaded or volatilesubstances are removed in the extruder. Further, it may also be added ina step of polymerizing rubber polymer for the same purposes asaforesaid.

The present inventors have made an extensive series of studies in orderto solve the above-described problems and, as a result, they found thatby controlling an amount of silicon to a specific level contained in athermoplastic resin composition [X] containing a specificrubber-reinforced vinyl resin, even when parts made of theabove-mentioned component [X] rub against each other, generation ofsqueaking noises is remarkably reduced, an effect of reducing squeakingnoises is maintained without deterioration even when being placed underhigh temperatures for a long time, and those are superior in impactresistance and molded appearance. The present invention has beencompleted on this finding.

According to the present invention, the following thermoplastic resincomposition for reduction of squeaking noises and a structure of reducedsqueaking noises are provided.

1. A thermoplastic resin composition [X] for reduction of squeakingnoises containing a rubber-reinforced vinyl resin [A] obtained bypolymerizing a vinyl monomer [b1] in the presence of anethylene-α-olefin rubber polymer [a1] having Tm (melting point) of 0° C.or higher,

wherein an amount of silicon contained in the thermoplastic resincomposition [X] is 0.15% by mass or less based on 100% by mass of thethermoplastic resin composition [X].

2. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1, wherein an amount of the ethylene-α-olefinrubber polymer [a1] is 5 to 30% by mass based on 100% by mass of thethermoplastic resin composition [X].

3. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 or 2, wherein the rubber-reinforced vinyl resin[A] contains the rubber-reinforced vinyl resin [A1] obtained bypolymerizing the vinyl monomer [b1] in the presence of theethylene-α-olefin rubber polymer [a1] having Tm (melting point) of 0° C.or higher, and a (co)polymer [B] of a vinyl monomer [b2].

4. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 3, wherein the ethylene α-olefin rubberpolymer [a1] comprises 5 to 95% by mass of ethylene and 95 to 5% by massof an α-olefin (provided that the total amount of the ethylene and theα-olefin is 100% by mass).

5. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 4, wherein a graft ratio of therubber-reinforced vinyl resin [A] is in a range of from 10 to 150% bymass, and an intrinsic viscosity [η] (measured at 30° C. in methyl ethylketone) of an acetone-soluble fraction is in a range of from 0.1 to 1.5dl/g.

6. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 5, wherein an intrinsic viscosity [η](measured at 30° C. in methyl ethyl ketone) of an acetone-solublefraction of the thermoplastic resin composition [X] is in a range offrom 0.1 to 1.5 dl/g.

7. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 6, wherein the ethylene-α-olefin rubberpolymer [a1] is an ethylene-propylene copolymer.

8. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 7, the amount of silicon contained in thethermoplastic resin composition [X] is 0.1% by mass or less based on100% by mass of the thermoplastic resin composition [X].

9. The thermoplastic resin composition for reduction of squeaking noisesof the above-mentioned 1 to 7, the amount of silicon contained in thethermoplastic resin composition [X] is 0.07% by mass or less based on100% by mass of the thermoplastic resin composition [X].

10. The thermoplastic resin composition for reduction of squeakingnoises of the above-mentioned 1 to 7, the amount of silicon contained inthe thermoplastic resin composition [X] is 0.03% by mass or less basedon 100% by mass of the thermoplastic resin composition [X].

11. A structure of reduced squeaking noises which comprises at least twocontacting parts, said contacting parts including a contacting part madeof the thermoplastic resin composition [X] defined in theabove-mentioned 1 to 10.

12. The structure of reduced squeaking noises of the above-mentioned 11,wherein two or more of the contacting parts are made of thethermoplastic resin composition [X] defined in the above-mentioned 1 to10.

13. The structure of reduced squeaking noises of the above-mentioned 12,wherein a noise risk measured by a stick-slip measuring instrumentSSP-02 manufactured by Zigler-Instruments GmbH is 3 or less undermeasuring conditions as set forth below:

Measuring conditions

Loads: 5N, 40N

Speeds: 1 mm/sec, 10 mm/sec

14. The structure of reduced squeaking noises of the above-mentioned 11to 13, wherein the contacting parts are for automobile interior parts,switch parts, business equipment parts, household electrical applianceparts, desk rock parts, housing interior parts or open-close damperparts of inside doors.

15. A meter visor for automobile interior parts which includes acontacting part made of the thermoplastic resin composition [X] definedin the above-mentioned 1 to 10.

16. A center panel for automobile interior parts which includes acontacting part made of the thermoplastic resin composition [X] definedin the above-mentioned 1 to 10.

17. A console box for automobile interior parts which includes acontacting part made of the thermoplastic resin composition [X] definedin the above-mentioned 1 to 10.

18. A switch bezel for automobile interior parts which includes acontacting part made of the thermoplastic resin composition [X] definedin the above-mentioned 1 to 10.

Advantageous Effects of the Invention

According to the present invention, controlling of an amount of siliconto a specific level contained in a thermoplastic resin composition [X]containing a specific rubber-modified vinyl resin makes it possible toobtain a structure of reduced squeaking noises, which reduces remarkablysqueaking noises when parts made of the above-mentioned component [X]rub against each other, which does not deteriorate the effect ofreducing squeaking noises even when being placed at high temperaturesfor a long time, and which is excellent in impact resistance and moldedappearance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram of a stick slip phenomenon.

FIGS. 2(a), (b), (c) and (d) are model diagrams of a stick slip.

EMBODIMENTS OF THE INVENTION

The present invention will be described in more detail below.

The thermoplastic resin composition [X] for reduction of squeakingnoises contains a rubber-reinforced vinyl resin [A] obtained bypolymerizing a vinyl monomer [b1] in the presence of anethylene-α-olefin rubber polymer [a1] having Tm (melting point) of 0° C.or higher,

wherein an amount of silicon contained in the thermoplastic resincomposition [X] is 0.15% by mass or less based on 100% by mass of thethermoplastic resin composition [X].

Meanwhile, in the present specification, “(co)polymerization” meanshomopolymerization and copolymerization, “(meth)acrylic” means acrylicand/or methacrylic, and “(meth)acrylate” means acrylate and/ormethacrylate.

1. Rubber-Reinforced Vinyl Resin [A] (Hereinafter Referred to Also as“Component [A]”):

Component [A] used in the present invention is a rubber-reinforced vinylresin [A1] singly, obtained by polymerizing a vinyl monomer [b1] in thepresence of an ethylene-α-olefin rubber polymer [a1] having Tm (meltingpoint) of 0° C. or higher, and/or, a mixture of [A1] and a (co)polymer[B] of a vinyl monomer [b2]. The (co)polymer [B] is obtained bypolymerizing a vinyl monomer [b2] in the absence of a rubber polymer.

1-1. Ethylene-α-Olefin Rubber Polymer [a1] (Hereinafter Referred to Alsoas “Component [a1]):

The ethylene-α-olefin rubber polymer [a1] used in the present inventionis not specifically limited if Tm (melting point) is 0° C. or higher.

Here, Tm is measured by DSC (differential scanning calorimetry) in whichan endothermic change is measured at a constant heating rate of 20°C./minute and a peak temperature of the obtained endothermic pattern isread. The particulars are described in JIS K7121-1987. The Tm ispreferably 0 to 120° C., more preferably 10 to 100° C., particularlypreferably 20 to 80° C. In cases where the Tm is less than 0° C., thereduction effect of squeaking noises lowers since the rubber polymerdoes not have crystallizability around room temperature where the partsare often used. Meanwhile, when the peak of endothermic change in theDSC measurement is not exhibited clearly, the rubber polymer does nothave crystallizability substantially. Accordingly, it is judged ashaving no Tm and it is not included in the rubber polymer having Tm of0° C. or higher. Consequently, the rubber polymer having no Tm is alsopoor in reduction effect of squeaking noises.

The presence of melting point (Tm) in the rubber polymer indicates thatit has a crystalline part. The presence of a crystalline part in therubber polymer, as mentioned above, suppresses occurrence of a stickslip phenomenon, and as a result, generation of squeaking noises ispresumably suppressed.

Further, glass transition temperature (Tg) of the rubber polymer ispreferably −20° C. or lower, more preferably −30° C. or lower,particularly preferably −40° C. or lower. In cases where the glasstransition temperature exceeds −20° C., impact resistance tends to beinsufficient. Meanwhile, the glass transition temperature can beobtained in the same manner as in Tm (melting point), using DSC(differential scanning calorimetry) according to JIS K7121-1987.

Examples of the α-olefin constituting the above-mentioned component [a1]include α-olefins having 3 to 20 carbon atoms, and specifically includepropylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene,1-octene, 1-decene, 1-dodecene, 1-hexadecene and 1-eicocene. Theseα-olefins may be used singly or in combination of two or more. Thenumber of carbon atoms of the α-olefin is preferably 3 to 20, morepreferably 3 to 12, and even more preferably 3 to 8. If the number ofcarbon atoms exceeds 20, the surface appearance of a molded article maybecome insufficient due to deterioration in copolymerizability. The massratio of ethylene α-olefin is usually 5 to 95:95 to 5, preferably 50 to95:50 to 5, and more preferably 60 to 95:40 to 5, particularlypreferable 70 to 90:30 to 10.

If the mass ratio of the α-olefin exceeds 95, impact strength of theobtained rubber-reinforced vinyl resin is insufficient, and if it isless than 5, sufficient impact resistance of the resin composition maynot be provided because the rubber elasticity of the rubber polymer [a1]becomes insufficient.

The Mooney viscosity (ML₁₊₄, at 100° C.; in accordance with JIS K6300)of the component [a1] is usually 5 to 80, preferably 10 to 65, and morepreferably 10 to 45. If the Mooney viscosity exceeds 80, the fluidity ofan obtained rubber-reinforced vinyl resin may become insufficient, andif the Mooney viscosity becomes less than 5, the impact resistance of anobtained molded article may become insufficient.

As the above-mentioned ethylene-α-olefin rubber polymer [a1], those notcontaining nonconjugated diene components are usually used in terms ofreduction of squeaking noises. As the nonconjugated diene components,5-ethylidene-2-norbornene, dicyclopentadiene or the like areexemplified. When the above-mentioned component [a1] contains thenonconjugated diene components, the amount blended is preferably 3% bymass or less based on 100% by mass of ethylene and α-olefin. If theamount blended of the nonconjugated components is more than 3% by mass,the crystallizability of rubbers lowers and the effect of reducingsqueaking noises tends to be insufficient. As the above-mentionedcomponent [a1], an ethylene-propylene copolymer, an ethylene-1-butenecopolymer and an ethlene-1-octene copolymer are more preferable, and theethylene-propylene copolymer is particularly preferable.

1-2. Vinyl Monomers [b1] to [b2]:

The vinyl monomers [b1] and [b2] each may, without any particularlimitations, be any polymerizable compound having an unsaturated bond.

The vinyl monomers [b1] and [b2] each usually include an aromatic vinylcompound and a vinyl cyanide compound. If necessary, othercopolymerizable vinyl monomers such as (meth)acrylic acid ester andmaleimide compounds, functional group-containing vinyl monomers havingone or more functional groups such as a carboxyl group, an acidanhydride group, a hydroxyl group, an amino group, an amide group, anepoxy group and an oxazoline group may be used in combination.

The vinyl monomer [b2] to be used for forming the (co)polymer [B] may beeither the same as or different from the vinyl monomer [b1].

As the above-mentioned aromatic vinyl compound, any compound having atleast one vinyl bond and at least one aromatic ring can be used withoutany particular limitations. Examples thereof include styrene,α-methylstyrene, o-methylstyrene, p-methylstyrene, vinyltoluene,β-methylstyrene, ethylstyrene, p-tert-butylstyrene, vinylxylene,vinylnaphthalene, monochlorostyrene, dichlorostyrene, monobromostyrene,dibromostyrene and fluorostyrene. These may be used singly or incombination of two or more. Among these, styrene and α-methylstyrene arepreferred.

Examples of the above-mentioned vinyl cyanide compound includeacrylonitrile and methacrylonitrile. These may be used singly or incombination of two or more. Among these, acrylonitrile is preferred.

Examples of the above-mentioned (meth)acrylic acid ester include acrylicacid esters such as methyl acrylate, ethyl acrylate, propyl acrylate,butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate,2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate and benzylacrylate; and methacrylic acid esters such as methyl methacrylate, ethylmethacrylate, propyl methacrylate, butyl methacrylate, amylmethacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexylmethacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexylmethacrylate, phenyl methacrylate and benzyl methacrylate. These may beused singly or in combination of two or more. Among these, methylmethacrylate is preferred.

Examples of the above-mentioned maleimide compound include maleimide,N-methylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, andN-phenylmaleimide. These may be used singly or in combination of two ormore. Among these, N-cyclohexylmaleimide and N-phenylmaleimide arepreferred.

Meanwhile, as a method for introducing a monomer unit composed of themaleimide compound into a polymer, there is a method in which maleicanhydride is copolymerized beforehand and then imidation is conducted.

Among the above-mentioned functional group-containing vinyl monomers,examples of unsaturated compounds having a carboxyl group includeacrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaricacid, itaconic acid, crotonic acid and cinnamic acid. These may be usedsingly or in combination of two more.

Examples of the unsaturated compound having an acid anhydride groupinclude maleic anhydride, itaconic anhydride and citraconic anhydride.These may be used singly or in combination of two or more.

Examples of the unsaturated compound having a hydroxyl group includehydroxystyrene, 3-hydroxy-1-propene, 4-hydroxyl-butene,cis-4-hydroxy-2-butene, trans-4-hydroxy-2-butene,3-hydroxy-2-methyl-1-propene, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylate and N-(4-hydroxyphenyl)maleimide. These may be used singlyor in combination of two or more.

Examples of the unsaturated compound having an amino group includeaminoethyl acrylate, propylaminoethyl acrylate, dimethylaminomethylacrylate, diethylaminomethyl acrylate, 2-dimethylaminoethyl acrylate,aminoethyl methacrylate, propylaminoethyl methacrylate,dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate,2-dimethylaminoethyl methacrylate, phenylaminoethyl methacrylate,p-aminostyrene, N-vinyldiethylamine, N-acetylvinylamine, acrylic amine,methacrylic amine and N-methylacrylic amine. These may be used singly orin combination of two or more.

Examples of the unsaturated compound having an amide group includeacrylamide, N-methylacrylamide, methacrylamide andN-methylmethacrylamide. These may be used singly or in combination oftwo or more.

Examples of the unsaturated compound having an epoxy group includeglycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether. Thesemay be used singly or in combination of two or more.

Examples of the unsaturated compound having an oxazoline group includevinyl oxazoline. These may be used singly or in combination of two ormore.

While the types and the used amounts of the vinyl monomers [b1] and [b2]are chosen according to the purpose, application, and so on, the totalamount of the aromatic vinyl compound and the vinyl cyanide compound isusually 30 to 100% by mass, preferably 50 to 100% by mass, and morepreferably 70 to 100% by mass based on 100% by mass of the whole portionof the vinyl monomers. The amount of the aforementioned othercopolymerizable vinyl monomer is usually 0 to 70% by mass, preferably 0to 50% by mass, and more preferably 0 to 30% by mass based on 100% bymass of the whole portion of the vinyl monomers. The amount of theaforementioned functional group-containing vinyl monomer is usually 0 to40% by mass, preferably 0 to 30% by mass, and more preferably 0 to 20%by mass based on 100% by mass of the whole portion of the vinylmonomers. The use ratio of the aromatic vinyl compound and the vinylcyanide compound (aromatic vinyl compound/vinyl cyanide compound) isusually 40 to 85% by mass/15 to 60% by mass, and preferably 45 to 85% bymass/15 to 55% by mass, particularly preferably 60 to 85% by mass/15 to40% by mass, provided that the total amount of these compounds is takenas 100% by mass.

1-3. Method for Producing of the Rubber-Reinforced Vinyl Resin [A]:

While the aforementioned rubber-reinforced vinyl resin [A] is a polymercomponent containing an ethylene-α-olefin rubber polymer [a1], theircontained mode is not particularly restricted.

The rubber-reinforced vinyl resin [A] usually contains a graft copolymerin which a (co)polymer of a vinyl monomer has been grafted to a rubberpolymer and a (co)polymer of a vinyl monomer not having grafted to arubber polymer. It is noted that the graft copolymer may contain arubber polymer to which no (co)polymer of a vinyl monomer has beengrafted.

Moreover, examples of the contained mode of the ethylene-α-olefin rubberpolymer [a1] are provided below:

(1) A case in which the ethylene-α-olefin rubber polymer [a1] iscontained in the form of graft copolymers.

(2) A case in which the ethylene-α-olefin rubber polymer [a1] iscontained in the form of non-graft copolymers.

Among these, (1) is preferred.

Examples of the rubber-reinforced vinyl resin [A] of the above-mentionedmode (1) are provided below:

[i] A rubber-reinforced vinyl resin [A1] obtained by polymerizing avinyl monomer [b1] in the presence of the ethylene-α-olefin rubberpolymer [a1].

[ii] A mixture composed of the above-mentioned [i] and a (co)polymer [B]of a vinyl monomer [b2] (hereinafter referred to also as “(co)polymer[B]”).

Among these, is particularly preferred since it is possible to adjustthe amount of the ethylene-α-olefin rubber polymer [a1] contained in therubber-reinforced vinyl polymer [A].

The rubber-reinforced vinyl resin [A] may be a combination of the above[i] and [ii].

Next, the method for producing of the rubber-reinforced vinyl resin [A1]will be described.

Examples of the polymerization method include conventionalpolymerization methods such as emulsion polymerization, solutionpolymerization, suspension polymerization and bulk polymerization. Inany of these methods, it is permissible to feed a vinyl monomer at onetime and make it react in the presence of a rubber polymer, and it isalso permissible to add a vinyl monomer dividedly or continuously andmake it react. Regarding the rubber polymer, the whole amount or a partof it may be added during the polymerization with the vinyl monomer andmade to react.

The amount of the rubber polymer used is usually 5 to 80% by mass, andpreferably 10 to 70% by mass, provided that the total of the rubberpolymer and the vinyl monomer is taken as 100% by mass.

The method for producing of the above-mentioned rubber-reinforced vinylresin [A1] is preferably solution polymerization and bulkpolymerization, and solution polymerization is more preferred. Those mayalso be used in combination.

When producing the rubber-reinforced vinyl resins [A1] by emulsionpolymerization, a polymerization initiator, a chain transfer agent, anemulsifier, water, and so on are usually used. When the rubber polymeris not in a latex form but in a solid form, it can be used after beingconverted into a latex form by reemulsification.

Examples of the polymerization initiator include redox polymerizationinitiators composed of organic peroxides such as cumene hydroperoxide,diisopropylbenzene hydroperoxide and paramenthane hydroperoxide, andreducing agents represented by saccharated pyrophosphoric acidformulation and sulfoxilate formulation; persulfates such as potassiumpersulfate; peroxides such as benzoyl peroxide (BPO), lauroyl peroxide,tert-butyl peroxylaurate and tert-butyl peroxymonocarbonate; and azopolymerization initiators such as 2,2′-azobis(isobutyronitrile). Thesemay be used singly or in combination of two or more. The amount of thepolymerization initiator to be used is usually 0.05 to 5% by mass, andpreferably 0.1 to 1% by mass based on the total amount of the vinylmonomer [b1].

The polymerization initiator is usually added to a reaction system atone time or continuously.

Examples of the chain transfer agent include mercaptans such asoctylmercaptan, n-dodecylmercaptan, tert-dodecylmercaptan,n-hexylmercaptan, n-hexadecylmercaptan, n-tetradecylmercaptan andtert-tetradecylmercaptan; terpinolenes, a dimer of α-methylstyrene,tetraethylthiuram sulfide, acrolein, methacrolein, allyl alcohol and2-ethylhexyl thioglycol. These may be used singly or in combination oftwo or more. The amount of the chain transfer agent to be used isusually 0.05 to 2% by mass based on the total amount of the vinylmonomer [b1].

The emulsifier includes anionic surfactants and nonionic surfactants.Examples of the anionic surfactants include sulfate of higher alcohols;salts of alkylbenzene sulfonic acids such as sodiumdodecylbenzenesulfonate; salts of aliphatic sulfonic acids such assodium laurylsulfate; salts of rosin acids, and salts of phosphoricacid. Examples of the nonionic surfactants include alkyl ester typecompounds of polyethylene glycol and alkyl ether type compounds ofpolyethylene glycol. These may be used singly or in combination of twoor more. The amount of the emulsifier to be used is usually 0.3 to 5% bymass based on the whole amount of the vinyl monomer [b1].

Emulsion polymerization can be carried out under conventional conditionsaccording to the types and the amounts of the vinyl monomer [b1], apolymerization initiator, and so on to be used. The latex obtained bythe emulsion polymerization is usually coagulated using a coagulant, thepolymer component is formed into a powdery form, which is then purifiedby washing with water and drying. As the coagulant, inorganic salts suchas calcium chloride, magnesium sulfate, magnesium chloride and sodiumchloride; inorganic acids such as sulfuric acid and hydrochloric acid;and organic acids such as acetic acid, lactic acid and citric acid, andso on are used. These may be used singly or in combination of two ormore. According to the performance required, it is also permissible todo washing after performing neutralization treatment by the addition ofan alkali component or an acid component after the coagulation.

When producing the rubber-reinforced vinyl resin [A1] by solutionpolymerization, a solvent, a polymerization initiator, a chain transferagent, and so on are usually used.

As the solvent, inert polymerization solvents to be used forconventional radical polymerization can be used; for example, aromatichydrocarbons such as ethylbenzene and toluene; ketones such as methylethyl ketone and acetone; halogenated hydrocarbons such asdichloromethylene and carbon tetrachloride; acetonitrile,dimethylformamide, and N-methylpyrrolidone can be used. These may beused singly or in combination of two or more.

Examples of the polymerization initiator include organic peroxides suchas ketone peroxides, dialkyl peroxides, diacyl peroxides, peroxyestersand hydroperoxides. These may be used singly or in combination of two ormore.

Examples of the chain transfer agent include mercaptans, terpinolenesand a dimer of α-methylstyrene. These may be used singly or incombination of two or more.

Solution polymerization can be carried out under conventional conditionsaccording to the types and the amounts of the vinyl monomer [b1], apolymerization initiator, and so on to be used. The polymerizationtemperature is usually within the range of 80 to 140° C. The productioncan also be performed without using any polymerization initiator in thesolution polymerization.

Also in the cases of bulk polymerization and suspension polymerization,conventional methods can be applied. As a polymerization initiator, achain transfer agent, and the like to be used for such methods, there isno particular limitation and the compounds exemplified in thedescription of the solution polymerization can be used.

1-5. Physical Property of Rubber-Reinforced Vinyl Resin [A]:

The graft ratios of the rubber-reinforced vinyl resin [A1] obtained inthe above-described manners are each usually 10 to 150% by mass,preferably 20 to 120% by mass, and particularly preferably 30 to 70% bymass. If the graft ratio is less than 10% by mass, impact resistance maybe insufficient because a density of the (co) polymer of the vinylmonomer [b1] grafted to the rubber polymer becomes low or the length ofthe graft chain becomes short. On the other hand, if the graft ratioexceeds 150% by mass, since a layer of the (co)polymer of the vinylmonomer [b1] on the surface of the rubber polymer becomes thick andfurther a layer of the (co)polymer grafted inside the rubber polymerdevelops, rubber elasticity decreases and, as a result, impactresistance may deteriorate.

The above-mentioned graft ratio can be calculated by the followingformula.

Graft ratio (% by mass)={(S−T)/T}×100

In the above formula, S is a mass (g) of an insoluble fraction obtainedby charging 1 gram of a rubber-reinforced vinyl resin into 20 ml ofacetone then shaking the mixture for 2 hours with a shaker under atemperature condition of 25° C., and then centrifuging the mixture for60 minutes with a centrifugal separator (rotation speed; 23,000 rpm)under a temperature condition of 5° C., thereby separating the insolublefraction and the soluble fraction, and T is a mass (g) of the rubberpolymer contained in 1 g of the rubber-reinforced vinyl resin. The massof the rubber polymer can be determined by a method of calculating itfrom a polymerization formulation and a polymerization conversion, amethod of determining it from an infrared absorption spectrum (IR), andso on.

The intrinsic viscosity [η] (measured at 30° C. in methyl ethyl ketone)of the acetone-soluble fraction of each of the rubber-reinforced vinylresins [A1] is usually 0.1 to 1.5 dl/g, and preferably 0.2 to 0.8 dl/g.When the intrinsic viscosity [η] is within the above range, a physicalproperty balance between moldability and impact resistance is excellent.

The measurement of the intrinsic viscosity [η] was performed by thefollowing method. First, the acetone-soluble fraction (if the rubberpolymer is an acrylic rubber, acetonitrile is used in place of acetone)of each of the rubber-reinforced vinyl resin [A1] was dissolved inmethyl ethyl ketone, so that five solutions differing in concentrationwere prepared. A reduced viscosity was measured using a Ubbelohdeviscosity tube at each concentration at 30° C., and from themeasurements an intrinsic viscosity [η] was determined. The unit isdl/g.

The intrinsic viscosity can be adjusted by appropriately choosing thetype and the amount of the chain transfer agent to be used inproduction, the type and the amount of the polymerization initiator tobe used, the polymerization temperature, and so on.

2. (Co)Polymer [B] (Hereinafter Referred to Also as “Component [B]”):2-1. Method for Producing a (Co)Polymer [B]:

The (co)polymer [B] can be produced by polymerizing a vinyl monomer [b2]in the absence of a rubber polymer by a conventional method such assolution polymerization, bulk polymerization, emulsion polymerizationand suspension polymerization. Such polymerization may be either thermalpolymerization using no polymerization initiator or catalyticpolymerization using a polymerization initiator.

2-2. Physical Properties of a (Co)Polymer [B]:

The intrinsic viscosity [η] (measured at 30° C. in methyl ethyl ketone)of the polymer [B] is usually 0.1 to 1.5 dl/g, and preferably 0.2 to 1.0dl/g. When the intrinsic viscosity [η] is within the above range, aphysical property balance between moldability and impact resistance isexcellent.

The measurement of the intrinsic viscosity [n] was performed by thefollowing method. First, the (co)polymer [B] was dissolved in methylethyl ketone, so that five solutions differing in concentration wereprepared. A reduced viscosity was measured using a Ubbelohde viscositytube at each concentration at 30° C., and from the measurements anintrinsic viscosity [η] was determined. The unit is dl/g.

The intrinsic viscosity can be adjusted by appropriately choosing thetype and the amount of the chain transfer agent to be used inproduction, the type and the amount of the polymerization initiator tobe used, the polymerization temperature, and so on.

3. Silicone Oil [C] (Hereinafter Referred to Also as “Component [C]”):

The silicone oil as the component [C] used in the present invention isused to prevent deterioration and discoloration of a rubber-reinforcedvinyl resin caused by raised temperature of the resin due to shear forcein an extruder when the rubber-reinforced vinyl resin is melted andkneaded or when volatile substances are removed in the extruder, andwell-known silicone oils can be used as far as they have apolyorganosiloxane structure. The silicone oil [C] may be either anunmodified silicone oil such as dimethyl silicone oil, methylphenylsilicone oil and methyl hydrogen silicone oil, or a modified siliconeoil in which various types of organic groups have been introduced to apart of a side chain in a polyorganosiloxane structure and/or oneterminal portion of a polyorganosiloxane structure, or both terminalportions of a polyorganosiloxane structure. As the modified siliconeoil, alkyl-modified silicone oil, alkyl-aralkyl-modified silicone oil,polyether-modified silicone oil, fluorine-modified silicone oil, higheralkoxy-modified silicone oil, higher fatty acid-modified silicone oil,methylstyryl-modified silicone oil, methyl chlorinated phenyl siliconeoil, methyl hydrogen silicone oil, amino-modified silicone oil,epoxy-modified silicone oil, carboxyl-modified silicone oil,acrylic-modified silicone oil, methacrylic-modified silicone oil,mercapto-modified silicone oil, phenol-modified silicone oil,carbinol-modified silicone oil, and the like can be used. These may beused singly or in combination of two or more.

The amount of the silicone oil [C] is 0.15% by mass or less in terms ofsilicon contained in the thermoplastic resin composition [X] based on100% by mass of the thermoplastic resin composition, preferably 0.1% bymass or less, more preferably 0.07% by mass or less, still morepreferably 0.03% by mass or less. If the amount of silicon contained inthe thermoplastic resin composition [X] exceeds 0.15% by mass, squeakingnoise are not only generated when the materials of the same kinds areused in combination, but silver streaks occur in the neighborhood of agate to thus deteriorate molded appearance.

The amount of silicon contained in the thermoplastic resin composition[X] was measured by a fluorescent X-ray analytical instrument “MagicXPRO” manufactured by PANalytial.

4. Thermoplastic Resin Composition [X]:

The thermoplastic resin composition [X] in the present invention isobtained by mixing the above-mentioned component [A] and, if necessary,the above-mentioned component [B], in a prescribed incorporatingproportion, and melt-kneading them. The amount of the above-mentionedcomponent [B] is preferably 5 to 70% by mass, more preferably 10 to 60%by mass, provided that the total amount of the component [A] and thecomponent [B] is taken as 100% by mass.

The intrinsic viscosity [η] (measured in methyl ethyl ketone at 30° C.)of the acetone-soluble fraction of the above-mentioned thermoplasticresin composition [X] is usually 0.1 to 1.5 dl/g, and preferably 0.3 to0.7 dl/g. If the intrinsic viscosity [η] is within the above range, aphysical property balance between moldability and impact resistance isexcellent.

The measurement of the intrinsic viscosity [n] was performed by thefollowing method. First, the acetone-soluble fraction (if the rubberpolymer is an acrylic rubber, acetonitrile-soluble fraction) of theabove-mentioned thermoplastic resin composition [X] was dissolved inmethyl ethyl ketone, so that five solutions differing in concentrationwere prepared. A reduced viscosity was measured using a Ubbelohdeviscosity tube at each concentration at 30° C., and from themeasurements an intrinsic viscosity [₁] was determined. The unit isdl/g.

The amount of the ethylene-α-olefin rubber polymer [a1] in the component[A] is 5 to 30% by mass, preferably 5 to 25% by mass, and particularlypreferably 5 to 20% by mass, provided that the above-mentionedthermoplastic resin composition [X] is taken as 100% by mass. If theamount is less than 5% by mass, the effect of reducing squeaking noisesand the moldability become poor, and if the amount exceeds 30% by mass,the heat resistance deteriorates.

The thermoplastic resin composition [X] of the present invention asmentioned above may contain, if necessary, various additives such as afiller, a nucleating agent, a lubricant, a heat stabilizer, anantioxidant, a UV absorber, a flame retardant, an antiaging agent, aplasticizer, an antibacterial agent and a colorant, as far as the objectof the present invention is not impaired.

Moreover, the thermoplastic resin composition [X] of the presentinvention may contain, if necessary, other resins, for example,polyethylene, polypropylene, polybutylene terephthalate, polyethyleneterephthalate, polyphenylene sulfide and polyamide, etc., as far as theobject of the present invention is not impaired.

The thermoplastic resin composition [X] of the present invention can beproduced by mixing respective components in a prescribed incorporationratio by using a Tumbler mixer or a Henschel mixer, and thenmelt-kneading them under appropriate conditions by using a mixingmachine such as a single screw extruder, a twin screw extruder, aBanbury mixer, a kneader, a roll and a feeder ruder. A preferredkneading machine is a twin screw extruder. In kneading respectivecomponents, it is permissible to knead the respective components at onetime and it is also permissible to incorporate and knead them dividedlyin multiple stages. Moreover, it is also permissible to performpelletization by using an extruder after kneading with a Banbury mixer,a kneader, or the like. Among fillers, in the case of one in a fibrousform it is preferred to use a method of feeding it at the way of anextruder by the use of a side feeder in order to prevent cutting duringkneading. The melt-kneading temperature is usually 200 to 300° C., andpreferably 220 to 280° C.

The thermoplastic resin composition [X] has preferably a noise risk of 5or less, more preferably 3 or less in every value measured under theconditions of 5N and 10N in load and 1 mm/sec and 10 mm/sec in speed, byuse of the contacting parts made of the same thermoplastic resincomposition [X] in a stick-slip test in which measurement is conductedby a method described in examples later using a stick-slip measuringinstrument “SSP-02” manufactured by Ziegler-Instruments GmbH. Accordingto the criteria of the German Automobile Industry Association (VD A203-260), if the noise risk is 3 or less, the criteria is passed.

5. Structure:

The structure of the present invention comprises at least two contactingparts assembled to come into contact with each other.

The structure of the present invention includes contacting partsobtained by molding the above-described thermoplastic resin composition[X], and preferably, two or more of the contacting parts comprise moldedarticles made of the above-described thermoplastic resin composition[X]. There are no limitations in the method of producing the contactingparts of the present invention from the thermoplastic resin composition[X], and it can be produced by a conventional method such as injectionmolding, injection compression molding, gas assisted injection molding,press molding, calender molding, T-die extrusion molding, profileextrusion molding and film molding.

There are no particular limitations with respect to other members withwhich the contacting part of the present invention comes into contact,and examples thereof are a thermoplastic resin including thethermoplastic resin composition [X] of the present invention, athermosetting resin, a rubber, an organic material, an inorganicmaterial and a metallic material. The contacting parts made of thethermoplastic resin composition [X] are effective particularly when atleast two contacting parts are both comprised of the thermoplastic resincomposition [X], and more effective when all of the contacting parts arecomprised of the thermoplastic resin composition [X] of the presentinvention.

Examples of the thermoplastic resin include polyvinyl chloride,polyethylene, polypropylene, AS resin, ABS resin, AES resin, ASA resin,PMMA, polystyrene, high impact polystyrene, EVA, polyamide (PA),polyethylene terephthalate, polybutylene terephthalate, polycarbonate(PC), polylactic acid, PC/ABS, PC/AES, PA/ABS and PA/AES. These can beused singly or in combination of two or more.

Examples of the thermosetting resin include phenol resin, epoxy resin,urea resin, melamine resin and unsaturated polyester resin. These can beused singly or in combination of two or more.

Examples of the rubber include various synthetic rubbers such aschloroprene rubber, polybutadiene rubber, ethylene-propylene rubber,SEBS, SBS and SIS, and natural rubbers. These can be used singly or incombination of two or more.

Examples of the organic material include an insulation board, an MDF(medium density fiberboard), a hard board, a particle board, a lumbercore, an LVL (laminated veneer lumber), an OSB (oriented stack board), aPSL (Para-Lum), a WB (wafer board), a hard fiber board, a soft fiberboard, a lumber core plywood, a board core plywood, a special coreplywood, a veneer core plywood, a stack sheet/board of paper impregnatedwith a tap resin, a board produced by mixing an adhesive with finechips/strips prepared by breaking (used) paper, and then compressing themixture under heating, and various types of wood. These can be usedsingly or in combination of two or more.

Examples of the inorganic material include calcium silicate board,flexible board, homocement board, gypsum board, sheathing gypsum board,reinforced gypsum board, gypsum lath board, decorated gypsum board,composite gypsum board, various ceramics and glass. These can be usedsingly or in combination of two or more.

Moreover, examples of the metallic material include iron, aluminum,copper and various alloys. These can be used singly or in combination oftwo or more.

The contacting parts in the present invention can be suitably used asvarious structures in automobile interior parts, business equipmentparts, housing interior parts, household electrical appliance parts, andthe like, which have parts contacting, jointing or engaging othermembers.

The automobile interior part can remarkably reduce squeaking noisesgenerated when it comes into contact and rubs against other members byvibration at the time of running. Moreover, it is excellent in safety atthe time of collision due to its ductile fracture. Examples of such anautomobile interior part include a door trim, a door lining, a pillargarnish, a console, a console box, a center panel, a door pocket, aventilator, a duct, an air-conditioner, a meter visor, an instrumentpanel upper garnish, an instrument panel lower garnish, an A/Tindicator, on-off switches (a slide part, a slide plate), a switchbezel, a grill front defroster, a grill side defroster, a lid cluster, acover instrument lower, masks (e.g., a mask switch and a mask radio), aglove box, pockets (e.g., a pocket deck and a pocket card), a steeringwheel horn pad, a switch part and exterior parts for car navigation.Among these, it can be used suitably for a ventilator of a car, a platevane of a ventilator for an air-conditioner of a car, a valve shutter, alouver, a switch part, exterior parts for car navigation, and so on.

The business equipment part can remarkably reduce squeaking noisesgenerated when it comes into contact with and rubs against othermembers, for example, by vibration at working of equipments andopen-close of a desk drawer. Moreover, it is excellent in safety at thetime of collision due to its ductile fracture. Examples of suchcontacting part for the business equipment part include an exteriorpart, an interior part, a part around a switch, a part of a movableportion, a desk rock part, a desk drawer, and so on.

The housing interior part can remarkably reduce squeaking noisesgenerated when it comes into contact with and rubs against othermembers, for example, by open-close of a door and a sliding door.Moreover, it is excellent in safety at the time of collision due to itsductile fracture. Examples of such housing interior part include a shelfdoor, a chair damper, a folding leg movable part of a table, a dooropen-close damper, a sliding door rail, a curtain rail, and so on.

The household electrical appliance part can remarkably reduce generatedwhen comes into contact with and rubs against other members, forexample, by vibration at the time of working of an instrument. Examplesof such household electrical appliance part include an exterior partsuch as a case, a howsing, etc., an interior part, a part around aswitch, a part of a movable portion, and the like.

EXAMPLES

Hereinafter, the present invention will be described more specificallyby way of examples. However, the present invention is not limited to theexamples unless departing from the spirit of the invention. In theexamples, part and % are on a mass basis, unless otherwise stated.

(1) Evaluation Methods:

The measuring methods of the amount of silicon and the variousevaluation items in the following Examples and Comparative Examples aredescribed below.

(1-1) Measuring Method of the Amount of Silicon

Using an injection molding machine “EC 40” manufactured by ToshibaMachine Co., Ltd., specimens having a length of 25 mm a width of 50 mmand a thickness of 2 mm made of the thermoplastic resin compositionsshown in Table 1 were injection-molded under the conditions of acylinder temperature of 250° C., an injection pressure of 50 MPa, and amold temperature of 60° C. Using a fluorescent X-ray analyticalinstrument “MagiX PRO” manufactured by PANalytial, the amount of siliconin an area of 25 mm diameter in a central portion of the specimen wasmeasured. The results are shown in Table 1.

(1-1) Squeaking Noise Evaluation I (Noise Risk Values) Examples 4-9,Comparative Examples 5-9

Using an injection molding machine “IS-170FA” manufactured by ToshibaMachine Co., Ltd., each of the thermoplastic resin compositions for thecontacting parts 1 and 2 shown in Table 2 was injection-molded under theconditions of a cylinder temperature of 250° C., an injection pressureof 50 MPa and a mold temperature of 60° C., to obtain theinjection-molded plate having a length of 150 mm, a width of 100 mm anda thickness of 4 mm.

The specimens having a length of 60 mm, a width of 100 mm and athickness of 4 mm and a length of 50 mm, a width of 25 mm and athickness of 4 mm were cut out by a discsaw, respectively from theabove-mentioned injection-molded plate, the end portions were beveledwith a sandpaper of a count #100, and fine burrs were removed by acutter knife to thus obtain two plates of a large size and a small sizeas specimens of the contacting parts 1 and 2.

The two specimens of the contacting parts 1 and 2 were aged for 300hours in an oven adjusted to 80° C.±5° C., then cooled at 25° C. for 24hours. The large size specimen as the contacting part 1 and the smallsize specimen as the contacting part 2 were fixed to a stick-slipmeasuring instrument “SSP-02” manufactured by Ziegler-Instrument GmbH,and the squeaking noises were evaluated from noise risk values obtainedby rubbing against each other at an amplitude of vibration of 20 mmthree times under the conditions of loads 5N and 40N, and speeds 1mm/sec and 10 mm/sec. As the noise risk value becomes large, occurrencerisk of squeaking noises becomes high. The results are shown in Table 2.

◯: Highest noise risk value under the conditions tested: 1-3

Δ: Highest noise risk value under the conditions tested: 4-5

x: Highest noise risk value under the conditions tested: 6-10

Examples 10

Using an injection molding machine “IS-170FA” manufactured by ToshibaMachine Co., Ltd., the thermoplastic resin composition for thecontacting part 1 shown in Table 2 was injection-molded under theconditions of a cylinder temperature of 250° C., an injection pressureof 50 MPa and a mold temperature of 60° C., to obtain theinjection-molded plate having a length of 150 mm, a width of 100 mm anda thickness of 4 mm.

The specimen having a length of 60 mm, a width of 100 mm and a thicknessof 4 mm was cut out by a discsaw from the above-mentionedinjection-molded plate, the end portions were beveled with a sandpaperof a count #100, and fine burrs were removed by a cutter knife to thusobtain the specimen of the contacting part 1.

Using an injection molding machine “IS-170FA” manufactured by ToshibaMachine Co., Ltd., polycarbonate resin “S-300 (trade name)” manufacturedby Mitsubishi Engineering-Plastics Corporation, as the thermoplasticresin composition for the contacting part 2 was injection-molded underthe conditions of a cylinder temperature of 270° C., an injectionpressure of 50 MPa and a mold temperature of 60° C.

The specimens having a length of 50 mm, a width of 25 mm and a thicknessof 4 mm was cut out by a discsaw, from the injection-molded plate with alength of 150 mm, a width of 100 mm and a thickness of 4 mm, the endportions were beveled with a sandpaper of a count #100, and fine burrswere removed by a cutter knife to thus obtain the specimen for thecontacting part 2.

The two specimens of the contacting parts 1 and 2 were aged for 300hours in an oven adjusted to 80° C.±5° C., then cooled at 25° C. for 24hours. The large size specimen as the contacting part 1 and the smallsize specimen as the contacting part 2 were fixed to a stick-slipmeasuring instrument “SSP-02” manufactured by Ziegler-Instrument GmbH,and the squeaking noises were evaluated from noise risk values obtainedby rubbing against each other at an amplitude of vibration of 20 mmthree times under the conditions of loads 5N and 40N, and speeds 1mm/sec and 10 mm/sec. As the noise risk value becomes large, occurrencerisk of squeaking noises becomes high. The results are shown in Table 2.

Example 11

Using an injection molding machine “IS-170FA” manufactured by ToshibaMachine Co., Ltd., the thermoplastic resin compositions for thecontacting part 1 shown in Table 2 was injection-molded under theconditions of a cylinder temperature of 250° C., an injection pressureof 50 MPa and a mold temperature of 60° C., to obtain theinjection-molded plate having a length of 150 mm, a width of 100 mm anda thickness of 4 mm.

The specimen having a length of 60 mm, a width of 100 mm and a thicknessof 4 mm was cut out by a discsaw from the above-mentionedinjection-molded plate, the end portions were beveled with a sandpaperof a count #100, and fine burrs were removed by a cutter knife to thusobtain the specimen for the contacting part 1.

The specimen made of SUS 304 having a length of 50 mm, a width of 25 mmand a thickness of 4 mm was prepared and the end portions were beveledwith a sandpaper of a count #100 and used as the specimen for thecontacting part 2.

The two specimens of the contacting parts 1 and 2 were aged for 300hours in an oven adjusted to 80° C.±5° C., then cooled at 25° C. for 24hours. The large size specimen as the contacting part 1 and the smallsize specimen as the contacting part 2 were fixed to a stick-slipmeasuring instrument “SSP-02” manufactured by Ziegler-Instrument GmbH,and the squeaking noises were evaluated from noise risk values obtainedby rubbing against each other at an amplitude of vibration of 20 mmthree times under the conditions of loads 5N and 40N, and speeds 1mm/sec and 10 mm/sec. As the noise risk value becomes large, occurrencerisk of squeaking noises becomes high. The results are shown in Table 2.

Example 12

Using an injection molding machine “IS-170FA” manufactured by ToshibaMachine Co., Ltd., each of the thermoplastic resin compositions for thecontacting part 1 shown in Table 2 was injection-molded under theconditions of a cylinder temperature of 250° C., an injection pressureof 50 MPa and a mold temperature of 60° C., to obtain theinjection-molded plate having a length of 150 mm, a width of 100 mm anda thickness of 4 mm.

The specimen having a length of 60 mm, a width of 100 mm and a thicknessof 4 mm was cut out by a discsaw from the above-mentionedinjection-molded plate, the end portions were beveled with a sandpaperof a count #100, and fine burrs were removed by a cutter knife to thusobtain the specimen for the contacting part 1.

The specimen made of glass having a length of 50 mm, a width of 25 mmand a thickness of 4 mm was prepared and the end portions were beveledwith a sandpaper of a count #100 and used as the specimen for thecontacting part 2.

The two specimens of the contacting parts 1 and 2 were aged for 300hours in an oven adjusted to 80° C.±5° C., then cooled at 25° C. for 24hours. The large size specimen as the contacting part 1 and the smallsize specimen as the contacting part 2 were fixed to a stick-slipmeasuring instrument “SSP-02” manufactured by Ziegler-Instrument GmbH,and the squeaking noises were evaluated from noise risk values obtainedby rubbing against each other at an amplitude of vibration of 20 mmthree times under the conditions of loads 5N and 40N, and speeds 1mm/sec and 10 mm/sec. As the noise risk value becomes large, occurrencerisk of squeaking noises becomes high. The results are shown in Table 2.

(1-1) Squeaking Noise Evaluation II (Practical Use Evaluation):

Using an injection molding machine “J-100E” (model name) manufactured byThe Japan Steel Works, Ltd., five ISO dumbbell specimens made of thethermoplastic resin compositions for the contacting parts 1 and 2 shownin Table 2 were injection-molded, respectively and these specimens wereleft at rest in a gear oven at 80° C. for 200 hours. Next, five ISOdumbbell specimens as the contacting part 1 and five ISO dumbbellspecimens as the contacting part 2 were stacked one on another to formstructures, and both ends thereof were twisted by hand, therebyevaluating a condition of squeaking noise generation. The evaluation wascarried out five times and judgment was done on the basis of thefollowing evaluation criteria. In addition, the dumbbell specimens leftat rest for 400 hours in a gear oven were also evaluated.

Evaluation of an Effect of Reducing Squeaking Noises:

◯: In all of the five evaluations, there was only slight generation ofsqueaking noises.Δ: In all of the five evaluations, a case where there was remarkablegeneration of squeaking noises was included (a case where there wasremarkable generation of squeaking noises in all of the five evaluationsis removed).x: In all of the five evaluations, there was remarkable generation ofsqueaking noises.

(1-3) Molded Appearance Evaluation (Silver Streaks)

Using an injection molding machine “EC40” manufactured by ToshibaMachine Co., Ltd., each of the thermoplastic resin compositions shown inTable 1 was injection-molded with a 1 mm-diameter center pin gate moldunder a cylinder temperature of 250° C., an injection pressure of 80 MPaand a mold temperature of 60° C. to obtain five disc-shaped moldedarticles having a diameter of 80 mm and a thickness of 2 mm. Theobtained five specimens were observed visually and the molded appearancewas evaluated according to the following criteria. The results are shownin Table 1.

◯: In all of the five specimens, there was no case where the silverstreaks occurred in the neighborhood of the gate.

x: In all of the five specimens, there was included a case where thesilver streaks occurred in the neighborhood of the gate.

Incidentally, the molded appearance of the structures was shown in Table2. This judged outer appearance of the whole of the structures accordingto the two-rank evaluation;

◯: good x: not good

Component [A] A-1: AES-1

A stainless steel autoclave having a volume of 20 liters equipped with aribbon type stirrer vane, a continuous aid feeder, a thermometer, etc.was charged with 22 parts of an ethylene-α-olefin-based rubber(ethylene-propylene copolymer having an ethylene/propylene=78/22(%) andMooney viscosity (ML₁₊₄, 100° C.) of 20, melting point (Tm) of 40° C.,glass transition temperature (Tg) of −50° C.), 55 parts of styrene, 23parts of acrylonitrile, 0.5 part of t-dodecyl mercaptan, and 110 partsof toluene, then the internal temperature was raised to 75° C., and thenthe content in the autoclave was stirred for 1 hour to form ahomogeneous solution. Then, 0.45 part of t-butyl peroxyisopropylmonocarbonate was added and the inner temperature was further raised.After the inner temperature reached 100° C., a polymerization reactionwas carried out at a stirring rotation speed of 100 rpm whilemaintaining that temperature. At a time of four hours after the start ofthe polymerization reaction, the internal temperature was raised to 120°C., and a reaction was further carried out for 2 hours while maintainingthat temperature, so that the polymerization reaction was finished.Then, the internal temperature was cooled to 100° C., and 0.2 part ofoctadecyl-3-(3,5-di-t-butyl-4-hydroxyphenol) propionate and 0.02 part ofdimethyl silicone oil; KF-96-100 cSt (trade name: manufactured byShin-Etsu Silicones) were added. Then, the reaction mixture was takenout from the autoclave, an unreacted substance and a solvent weredistilled off therefrom by steam distillation, and moreover volatilecomponents were removed substantially completely by using a 40 mm φextruder having a vent (cylinder temperature: 220° C., degree of vacuum:760 mmHg), thereby forming pellets. The resulting ethylene-α-olefinrubber-reinforced vinyl resin had a graft ratio of 70% and the intrinsicviscosity [η] of its acetone-soluble fraction was 0.47 dl/g.

A-2: AES-2

A stainless steel autoclave having a volume of 20 liters equipped with aribbon type stirrer vane, a continuous aid feeder, a thermometer, etc.was charged with 30 parts of an ethylene-propylene-dicyclopentadienecopolymer (ethylene/propylene/dicyclopentadiene=63/32/5(%) and a Mooneyviscosity (ML₁₊₄, 100° C.) of 33, no melting point (Tm), and glasstransition temperature (Tg) of −52° C.), in place of ethylene-α-olefinrubber polymer used in A-1, 45 parts of styrene, 25 parts ofacrylonitrile, 0.5 part of t-dodecyl mercaptan, and 140 parts oftoluene, then the internal temperature was raised to 75° C., and thenthe content in the autoclave was stirred for 1 hour to form ahomogeneous solution. Then, 0.45 part of t-butyl peroxyisopropylmonocarbonate was added, and the internal temperature was furtherraised. After the inner temperature reached 100° C., a polymerizationreaction was carried out at a stirring rotation speed of 100 rpm whilemaintaining that temperature. At a time of four hours after the start ofthe polymerization reaction, the internal temperature was raised to 120°C., and a reaction was further carried out for 2 hours while maintainingthat temperature, so that the polymerization reaction was finished.Then, the internal temperature was cooled to 100° C. and 0.2 part ofoctadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenol)propionate and 0.02 partof dimethyl silicone oil; KF-96-100 cSt (trade name: manufactured byShim-Etsu Silicones) were added. Then, the reaction mixture was takenout from the autoclave, an unreacted substance and a solvent weredistilled off therefrom by steam distillation, and moreover volatilecomponents were removed substantially completely by using a 40 mm φextruder having a vent (cylinder temperature: 220° C., degree of vacuum:760 mmHg), thereby forming pellets. The resulting ethylene-α-olefinrubber-reinforced vinyl resin had a graft ratio of 60%, and theintrinsic viscosity [η] of its acetone-soluble fraction was 0.45 dl/g.

A-3: ABS-1

A polymerization vessel equipped with a stirrer was charged with 280parts of water, 60 parts (in terms of solid) of polybutadiene latexhaving a weight average particle diameter of 0.26 μm and a gel fractionof 90%, 0.3 part of sodium formaldehyde sulfoxylate, 0.0025 part offerrous sulfate, and 0.01 part of disodium ethylenediaminetetraacetate,followed by deoxygenation. After heating to 60° C. under stirring undera nitrogen flow, a monomer mixture composed of 10 parts ofacrylonitrile, 30 parts of styrene, 0.2 part of t-dodecyl mercaptan, and0.3 part of cumene hydroperoxide was dropped at 60° C. continuously over5 hours. After completion of the dropping, the polymerizationtemperature was raised to 65° C., and the polymerization was completedafter continuing stirring for 1 hour, so that a latex of a graftcopolymer was obtained. The polymerization conversion was 98%. Then, theresulting latex was coagulated by adding 0.2 part of2,2′-methylene-bis(4-ethylene-6-t-butylphenol) and calcium chloridethereto, and a resin composition in a powder form was obtained afterwashing, filtration, and drying steps. The graft ratio of the resultingresin composition was 40% and the intrinsic viscosity [η] of theacetone-soluble fraction was 0.38 dl/g.

B-1: AS-1

A synthetic apparatus obtained by connecting two jacketed polymerizationreactors equipped with a ribbon type stirrer vane was used.

Each reactor was purged with nitrogen gas and the first reactor wascharged continuously with a mixture of 75 parts of styrene, 25 parts ofacrylonitrile and 20 parts of toluene, a solution dissolving 0.15 partof tert-dodecyl mercaptan as a molecular weight modifier in 5 parts oftoluene, and a solution dissolving 0.1 part of dicumylperoxide as apolymerization initiator in 5 parts of toluene and the polymerizationwas conducted at 110° C. The average retention time of monomers etc.,charged was 2 hours and the polymerization conversion after 2 hours was56%.

Next, the obtained polymer solution was taken out continuously by a pumplocated at an exterior of the first reactor and fed to the secondreactor. The amount taken out continuously was the same as fed to thefirst reactor. In the second reactor the polymerization was conducted at130° C. for 2 hours and the polymerization conversion after 2 hours was74%.

Thereafter, the polymer solution was recovered from the second reactorand introduced into a three vent-type twin-screw extruder and unreactedmonomers and toluene (solvent for polymerization) were removed directlyand the styrene-acrylonitrile copolymer was recovered. Thisstyrene-acrylonitrile copolymer was used as the component [B-1]. Theintrinsic viscosity [η] (methyl ethyl ketone, 30° C.) of this component[B-1] was 0.60 dl/g.

(2-2) Component [C] (Silicone Oil):

C-1: Dimethyl silicone oil; KF-96-100 cSt (trade name: produced byShin-Etsu Silicones), whose kinematic viscosity at 25° C. was 100 cSt.

(2-3) Component [D] (Additives):

D-1: Ethylene-bisstearic acid amide; KAOWAX EB-P (trade name: producedby Kao Corp.)D-2:1,3,5-Tris(3,5-di-t-butyl-4-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione;ADK STAB AO-20 (trade name: produced by ADEKA Corp.)D-3: Bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite; ADK STABPEP-24G (trade name: produced by ADEKA Corp.)

Examples 1-3 and Comparative Examples 1-4

The thermoplastic resin compositions comprising the above-describedcomponents [A] to [D] were mixed in the incorporation ratios shown inTable 1 by using a Henschel mixer, and then were kneaded in a twin screwextruder (manufactured by The Japan Steel Works, Ltd., TEX44 α, barrelpreset temperature 250° C.), so that thermoplastic resin compositions Xand Y were pelletized.

Using the obtained resin compositions X and Y, specimens for evaluationas described above were molded. Using the specimens obtained,evaluations were carried out by the methods described above. The resultsof the evaluations are shown in Table 1.

TABLE 1 Examples Comparative Examples 1 2 3 1 2 3 4 Resin compositionsX1 X2 X3 X4 X5 Y1 Y2 Formulation Rubber-reinforced vinyl resins [A] A-1AES-1 Parts 50 50 50 50 A-2 AES-2 Parts 40 A-3 ABS-1 Parts 25 25 (Co)polymer [B] B-1 AS-1 Parts 50 50 50 60 50 75 75 Silicone oil [C] C-1Parts 0.1 0.3 0.5 0.5 Additives [D] D-1 Parts 0.5 0.5 0.5 0.5 0.5 0.50.5 D-2 Parts 0.1 0.1 0.1 0.1 0.1 0.1 0.1 D-3 Parts 0.2 0.2 0.2 0.2 0.20.2 0.2 Amount Rubber polymer [a1] wt % 11 11 11 12 11 10 10 Silicon wt% 0.0047 0.0508 0.1430 0.0040 0.2340 0.0000 0.2310 PropertyAcetone-soluble fraction [η] dl/g 0.54 0.54 0.54 0.54 0.54 0.59 0.59Evaluation Molded appearance (silver streaks) ◯ ◯ ◯ ◯ X ◯ X AES-1: 0.02part of silicone oil was used at the time of polymerization AES-2: 0.02part of silicone oil was used at the time of polymerization

TABLE 2 Examples Comparative Examples Structures 4 5 6 7 8 9 10 11 12 56 7 8 9 Compositions for contacting part 1 X1 X2 X3 X1 X1 X1 X1 X1 X1 X4X5 Y1 Y2 Y1 Compositions for contacting part 2 X1 X2 X3 X3 X5 Y1 Y3 Y4Y5 X4 X5 Y1 Y2 Y2 Squeaking I 5N, 1 mm/s 1 1 3 1 1 1 1 1 1 5 4 10 10 10noise Noise risk values 5N, 10 mm/s 1 2 2 2 2 2 2 2 2 7 2 10 10 10evaluation 40N, 1 mm/s 1 1 5 1 1 1 1 1 1 5 10  10 10 10 40N, 10 mm/s 1 33 3 3 3 3 3 3 9 3 10 10 10 II 200 hours ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ X X X XPractical use evaluation 400 hours ◯ ◯ ◯ ◯ ◯ ◯ ◯ — — X X X X X Moldedappearance (silver streaks) ◯ ◯ ◯ ◯ X ◯ ◯ — — ◯ X ◯ X X Recycle property◯ ◯ ◯ X X X X X X ◯ ◯ ◯ ◯ X —: Not evaluated.

Examples 4-12 and Comparative Examples 5-9

Using the resin compositions obtained in the above-mentioned Examples1-3 and Comparative Examples 1-4, the contacting parts 1 and 2 wereproduced in the above-mentioned methods, and the structures wereprepared by combining these contacting parts as shown in Table 2. Thesqueaking noise, the molded appearance and the recycle property wereevaluated in the above-mentioned methods.

Moreover, using as the contacting part 2 polycarbonate [Y3], metal(stainless) [Y4] and glass [Y5], the structures combining those with thecontacting part 1 were produced and evaluated in the same way asaforesaid. The evaluation results are shown in Table 2.

As is shown in Table 1, the resin compositions X1 to X3 of the presentinvention represented by Examples 1 to 3 are all superior in moldedappearance.

In contrast, the resin compositions X5 and Y2 in Comparative Example 2and Comparative Example 4 are cases in which the amount of silicon istoo large and thus those are inferior in molded appearance. The resincompositions X4 and Y1 in Comparative Example 1 and Comparative Example3 contain less amount of silicon and thus those are superior in moldedappearance.

Further, as is shown in Table 2, the structures using the resincompositions X1 to X3 of the present invention represented by Examples 4to 6 are superior in squeaking noise evaluation and molded appearance.Moreover, the structures using the same resin compositions X1, X2 and X3for the contacting parts 1 and 2 are good in recycle property since theseparation of the resin compositions are not necessary.

The structure of Example 7 is a case in which the resin compositions X1and X3 are combined, and this is superior in squeaking noise evaluationbut inferior in recycle property.

The structure of Example 8 is a case in which the resin composition X1and the resin composition X5 containing two much silicon, and this issuperior in squeaking noise evaluation but inferior in molded appearanceand recycle property.

The structures of Examples 10 to 12 are cases in which the resincomposition X1 and the materials of different kinds, and those aresuperior in squeaking noise evaluation but inferior in recycle propertysince separation of the resin compositions from materials of differentkinds is necessary.

On the other hand, the structure of Comparative Example 5 is a case inwhich as the contacting parts 1 and 2, the resin compositions X4 and X4containing the rubber-reinforced vinyl resin [A-2] using theethylene-α-olefin rubber polymer [a1] having no melting point (Tm) arecombined, and this is inferior squeaking noise evaluation.

The structure of Comparative Example 6 is a case in which as thecontacting parts 1 and 2, the resin compositions X5 and X5 containingtoo much silicon are combined, and this is inferior in squeaking noiseevaluation and molded appearance.

The structure of Comparative Example 7 is a case in which as thecontacting parts 1 and 2, the resin compositions Y1 and Y1 containingthe rubber-reinforced vinyl resin [A-3] using the polybutadiene rubberpolymer in place of the ethylene-α-olefin rubber polymer [a1] arecombined, and this is inferior in squeaking noise evaluation.

The structure of Comparative Example 8 is a case in which as thecontacting parts 1 and 2, the resin compositions Y2 and Y2 containingthe rubber-reinforced vinyl resin [A-3] using the polybutadiene rubberpolymer in place of the ethylene-α-olefin rubber polymer [a1] arecombined, and this is inferior in squeaking noise evaluation and moldedappearance.

The structure of Comparative Example 9 is a case in which as thecontacting parts 1 and 2, the resin compositions Y1 and Y2 containingthe rubber-reinforced vinyl resin [A-3] using the polybutadiene rubberpolymer in place of the ethylene-α-olefin rubber polymer [a1] arecombined, and this is inferior in squeaking noise evaluation and moldedappearance, and further inferior in recycle property since separation ofthe resin composition Y1 from the resin composition Y2 is necessary.

As apparent from the above, it is understood that the thermoplasticresin composition of the present invention exhibits an excellent effectof reducing squeaking noise with respect to various materials,regardless of kinds of materials of the contacting parts to beassembled, and therefore it is suitable for automobile interior parts,business equipment parts, housing interior pars, household electricalappliance parts and the like, which have portions contacting, jointingor engaging with other members.

INDUSTRIAL APPLICABILITY

The thermoplastic resin composition for reduction of squeaking noises ofthe present invention can provide a structure comprised of contactingparts, which is characterized in that generation of squeaking noisesthat are generated when members rub against each other is remarkablyreduced, that an effect of reducing squeaking noises is maintainedwithout deterioration even when being placed under high temperatures fora long time, and further that impact resistance is superior. It can beused suitably for automobile interior parts, business equipment parts,housing interior parts, household electrical appliance parts, and so on,which have portions contacting, jointing or engaging with other members.

DESCRIPTION OF REFERENCE SIGNS

-   -   M Object    -   V Driving speed    -   μs Coefficient of static friction of the upper end of saw wavy        form    -   μl Coefficient of friction of the lower end of saw wavy form    -   Δμ μs-μl

1-18. (canceled)
 19. A structure of reduced squeaking noises whichcomprises at least two contacting parts assembled to come into contactwith each other, wherein the at least two contacting parts are made of athermoplastic resin composition [X] consisting of: a rubber-reinforcedvinyl resin [A] obtained by polymerizing a vinyl monomer [b1] in thepresence of an ethylene-α-olefin rubber polymer [a1] consisting ofethylene and an α-olefin having Tm (melting point) of 0° C. or higher;and a silicone oil, and wherein an amount of silicon derived from thesilicone oil contained in the thermoplastic resin composition [X] ismore than 0.03% by mass and not more than 0.15% by mass based on 100% bymass of the thermoplastic resin composition [X].
 20. The structure ofreduced squeaking noises according to claim 19, wherein an amount of theethylene-α-olefin rubber polymer [a1] is 5 to 30% by mass based on 100%by mass of the thermoplastic resin composition [X].
 21. A structure ofreduced squeaking noises which comprises at least two contacting partsassembled to come into contact with each other, wherein the at least twocontacting parts are made of a thermoplastic resin composition [X]consisting of: a rubber-reinforced resin containing a rubber-reinforcedvinyl resin [A] obtained by polymerizing a vinyl monomer [b1] in thepresence of an ethylene-α-olefin rubber polymer [a1] consisting ofethylene and an α-olefin having Tm (melting point) of 0° C. or higherand a (co)polymer [B] of a vinyl monomer [b2]; and a silicone oil, andwherein an amount of silicon derived from the silicone oil contained inthe thermoplastic resin composition [X] is more than 0.03% by mass andnot more than 0.15% by mass based on 100% by mass of the thermoplasticresin composition [X].
 22. The structure of reduced squeaking noisesaccording to claim 19, wherein the ethylene α-olefin rubber polymer [a1]consists of 5 to 95% by mass of ethylene and 95 to 5% by mass of anα-olefin (provided that the total amount of the ethylene and theα-olefin is 100% by mass).
 23. The structure of reduced squeaking noisesaccording to claim 19, wherein a graft ratio of the rubber-reinforcedvinyl resin [A] is in a range of from 10 to 150% by mass, and anintrinsic viscosity [η] (measured at 30° C. in methyl ethyl ketone) ofan acetone-soluble fraction of the thermoplastic resin composition [X]is in a range of from 0.1 to 1.5 dl/g.
 24. The structure of reducedsqueaking noises according to claim 19, wherein an intrinsic viscosity[η] (measured at 30° C. in methyl ethyl ketone) of an acetone-solublefraction of the thermoplastic resin composition [X] is in a range offrom 0.1 to 1.5 dl/g.
 25. The structure of reduced squeaking noisesaccording to claim 19, wherein the ethylene-α-olefin rubber polymer [a1]is an ethylene-propylene copolymer.
 26. The structure of reducedsqueaking noises according to claim 19, wherein a noise risk measured bya stick-slip measuring instrument SSP-02 manufactured byZigler-Instruments GmbH is 3 or less under all measuring conditions asset forth below: Measuring conditions Loads: 5N, 40N Speeds: 1 mm/sec,10 mm/sec.
 27. The structure of reduced squeaking noises according toclaim 19, wherein the contacting parts are for automobile interiorparts, switch parts, business equipment parts, household electricalappliance parts, desk rock parts, housing interior parts or open-closedamper parts of inside doors.
 28. The structure of reduced squeakingnoises according to claim 19, wherein the contacting parts are a metervisor for automobile interior parts.
 29. The structure of reducedsqueaking noises according to claim 19, wherein the contacting parts area center panel for automobile interior parts.
 30. The structure ofreduced squeaking noises according to claim 19, wherein the contactingparts are a console box for automobile interior parts.
 31. The structureof reduced squeaking noises according to claim 19, wherein thecontacting parts are a switch bezel for automobile interior parts.